Manufacturers of microelectronic devices that contain integrated circuits (“IC's”) typically use burn-in testing procedures on the microelectronic devices to test for latent failures that may occur in the IC. One standard testing regimen involves placing microelectronic devices into a burn-in chamber, raising the temperature of the microelectronic devices, and then applying nominal or stress voltages to them. The voltages are usually between 1.0-2.0 times the normal operating voltage of the IC and the stress usually ranges between 3-100 hours.
Current microelectronic devices fit generally within an economical burn-in envelope. Burn-in temperature is adjusted by changing the ambient air temperature and/or adjusting the microelectronic device toggle frequency to change the dynamic power. Unfortunately, high-voltage conditions tend to increase the problem of leakage power in the microelectronic devices. One method of dealing with this problem has been to decrease the toggle rate of the microelectronic devices and also to depopulate the heat chamber to keep within a total heat budget. However, there is no longer much room to decrease the frequency of modern microelectronic devices. Moreover, depopulation does not address the problem of leakage in individual units that can go into thermal runaway.